Tailgate loaders are generally known, in which a parallelogram linkage connected between a portion of the chassis at the rear of a truck and a platform is adapted to raise and lower the platform in such a way that the platform remains horizontal or substantially so. The raising and lowering is typically accomplished hydraulically, with a hydraulic cylinder being connected in such a way that it can be used to change the length of a diagonal of the parallelogram, thus causing the rear portion of the parallelogram linkage to move either up or down. In a typical installation, the power would be applied in order to raise the platform, and gravity would be used to lower the platform.
The platforms of tailgate loaders are typically stored either in a vertical position, in which they rest up against the back doors of the truck, or in a stored position under the rear upper chassis of the truck. This invention relates to arrangements in which the platform can be stored under the upper chassis at the rear of the truck.
Typically, the platform is pivotally mounted to what constitutes a vertical link at the rear end of the parallelogram linkage. The platform is ordinarily constructed in such a way that it can, while extending rearwardly from the parallelogram linkage, only pivot downwardly to a given predetermined position, typically one in which it is approximately parallel with the ground (horizontal). Further pivoting of the frame is prevented by mechanical interference between a flange or bracket and the rearward vertical link of the parallelogram linkage. To place the platform in a stored position, the platform is swung upwardly, through the vertical "dead centre" position, and then inwardly and downwardly to overlie the parallelogram linkage itself.
Generally, the platforms utilized in tailgate loaders are quite heavy, and it is an aspect of this invention to provide a tailgate loader construction which is such that it does not require great effort on the part of the operator to move the platform from the stored position to the extended position.